The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
Not applicable.
(1) Field of the Invention
This invention generally relates to a spacing device for towed arrays.
More particularly, the invention relates to a hydraulically activated toroidal aperture generation system in which spacing is provided for towed arrays.
(2) Description of the Prior Art
The current art for an aperture generation system is a passive system presently used by the Near Term Multi-Line Towed Array (NTMLTA). This known system cannot be used to vary the relative location of the individual towed lines. In addition, there are concerns regarding the reliability, manufacturability and environmental compatibility of the current known system.
Accordingly, a problem exists in the art of multiple line towed arrays to provide a means for reliably generating and maintaining separation of the lines in a specified three-dimensional configuration. Any system for aperture generation (or generation of a mechanically maintained, three-dimensional spacing between the towed lines) must be compatible with the method of deploying and retrieving the towed system. For the present technology, this requires that the aperture generation system collapse to a significantly reduced volume prior to retrieval. An ideal system would also operate automatically with no power or outside intervention. Accordingly, any new system must operate under the following constraints:
Maintain separation distances across relevant operation speed ranges; Allow deployment and retrieval of the towed system and proper operation of the sensors; Survive flank speed of tow platform; Operate reliably in a seawater environment, temperature range compliance, hydrostatic pressure compliance, and material compatibility; and Maintain performance for a minimum of three months without maintenance in a submarine environment.
The following patents, for example, disclose towed lines and cable arrangements, but do not disclose a hydraulically activated device for vertically and horizontally separating plural towed arrays.
U.S. Pat. No. 4,108,101 to Schirtzinger;
U.S. Pat. No. 4,726,315 to Bell et al.;
U.S. Pat. No. 4,958,331 to Wardle;
U.S. Pat. No. 5,835,450 to Russell;
U.S. Pat. No. 5,855,179 to Wood;
U.S. Pat. No. 5,863,440 to Rink et al.;
U.S. Pat. No. 5,983,821 to Williams;
U.S. Pat. No. 6,058,072 to Abraham; and
U.S. Pat. No. 6,143,172 to Rink et al.
Specifically, Shirtzinger discloses an arrangement for transporting in which a self-propelled surface vessel tows a submergible elongated cargo container by means of a semi-rigid boom extending from the stern of the vessel to the nose of the cargo container. The position of the boom is controlled from the stern of the vessel to hold the nose of the container at a level below the wake of the towing vessel.
The patent to Bell et al. discloses a ship provided with booms that may be extended outwardly from the ship. Geophysical devices of different genera are towed from the booms, in the water behind the ship. A UHF antenna is located at the outboard top of each boom. A line joining the two antennas defines a long reference base line for determining the absolute heading of the ship with respect to a meridian and to locate the absolute positions of selected towed geophysical devices with respect to two-dimensional space. The booms may be automatically oriented along a line perpendicular to the ship""s track, independently of the ship""s heading.
Wardle discloses a mobile sonar surveillance system having a fully populated circular shaped horizontal receiving array steered in edgefired directions with overlapping coverage of beams. The array has a plurality of hydrophones randomly spaced and mounted on a series of parallel lines in the same horizontal plane and is suitable for towing by a single small ship. For alignment of a received signal, one or more single beams suitable for rotation can be steered azimuthally with the proper set of synchronized variable delays. These beams will retain approximately the same parameters as they rotate.
Russell discloses a system for transmitting signals between a plurality of towed sensor streamers and a seismic vessel, the system comprising: a plurality of seismic streamers, wherein each streamer of the plurality of seismic streamers comprises: a leading end, a trailing end, a plurality of sensors located therein and a transmitter of seismic signals received by the plurality of sensors to a terminal located in the leading end of the streamer; at least one spreader located between the streamers, the spreader comprising: connectors for connecting to the terminals of the streamers, a spreader terminal, and a spreader transmitter of signals between the connectors and the spreader terminal; a lead-in having a lead-in connector for connecting to the spreader terminal and a transmitter of signals between the lead-in connector and the seismic vessel. A seismic streamer system is disclosed comprising: a lead-in, and multiple streamers; wherein the multiple streamers are signal-connected to the lead-in, and wherein at least two of the streamers are signal-connected by at least one spreader. A process is disclosed comprising: transmitting signals between at least two streamers of a plurality of streamers; transmitting signals between a first lead-in and the plurality of streamers; and transmitting signals between the first lead-in and the vessel. A process is disclosed comprising: transmitting signals between each streamer of the plurality of streamers and a spreader bus; transmitting signals between the spreader bus and at least one lead-in, wherein the number of streamers of the plurality of streamers is greater than the number of lead-ins; and transmitting signals through at least one lead-in to the vessel.
The patent to Wood discloses a towed array handling system for installation within the enlarged sails of future submarines. The system has a large diameter reel that provides storage for the entire array and tow cable when not deployed. The area within the enlarged sail is sufficient to allow for a dual winch and reel system for separately storing and deploying single line and/or multi line arrays. The reel applies the full tension of the streamed array as it is deployed and retrieved. When locked, the reel applies the full array streaming tension during high-speed tow. The towed array is ducted from the winch to an amidships tow point via a guide path through a ballast tank which contains only two bends. The upper sheave at the bend closest to the winch is free-wheeling and the lower sheave is part of a transfer device which pulls the array from the winch during the initial phase of deployment. The guide duct is aligned with the winch to provide even spooling of the array, especially the multi line array, onto the winch.
Rink et al. ""440 discloses a :plurality of water- and oil-porous sacks partially filled with a number of generally toroidal bodies of a polymer material that entraps oil and including mesh fragments scattered throughout the bodies. Each sack is sewn with a perimeter stiffening ring, to retain a flat profile, and has a netting that closes to help inhibit outflow of the oil when the sack is retrieved. When deployed from ship or by air onto a spill, the sacks spread into a pancake shape and the polymer matter forms a single layer that retains the oil. The sacks will float indefinitely without releasing the oil or allowing it to emulsify, so the oil can remain in place until collection efforts are feasible. The sacks can be burned in situ, or standard fishing boats or specialized collection boats can be burned to capture the energy content of the oil or processed to separate the oil from the polymer. The sacks can be used in conjunction with other, known containment or retrieval equipment, such as booms or skimmers. The system is specifically designed for rapid deployment and efficiency in rough water.
The patent to Williams discloses a multiline tow cable assembly including swivel area components and slip ring components. The swivel area components include a rotor member connected to an external housing, at least one contact member formed within the rotor member and rotatable with the rotor, and first electrical leads connected to the at least one contact member. The slip ring components include a multiline termination member, a stator connected to the multiline termination member, at least one contact pin formed in connection with the stator, and second electrical leads connected to the at least one contact pin. A substantially friction free member is interposed between the swivel area components and the slip ring components for enabling relative rotation of the swivel area components with respect to the slip ring components. With the described assemblies, continuous electrical connection is maintained between the first and second electrical leads upon rotation of the swivel area components with respect to the slip ring components.
Abraham discloses a system and method for reducing flow-induced noise in an underwater towed system. The system includes at least one neutrally buoyant towed array, a tow platform for defining a tow direction of the at least one towed array, a neutrally buoyant tow cable connected to the at least one towed array and the tow platform, and a deploy and retrieve apparatus for deploying and retrieving the tow cable. The deploy and retrieve apparatus is connected to both the tow cable and the tow platform. Deployment of the tow cable from the deploy and retrieve apparatus correspondingly deploys the at least one towed array, and retrieval of the tow cable with the deploy and retrieve apparatus correspondingly retrieves the at least one towed array. The speed of deployment of the tow cable can be varied to decrease the velocity of the towed array relative to the surrounding water thus reducing flow-induced noise.
Rink et al. ""172 discloses a plurality of water- and oil-porous sacks partially filled with a number of generally toroidal bodies of a polymer material that entraps oil and including mesh fragments scattered throughout the bodies. Each sack is sewn with a perimeter stiffening ring, to retain a flat profile, and has a netting that closes to help inhibit outflow of the oil when the sack is retrieved. When deployed from ship or by air onto a spill, the sacks spread into a pancake shape and the polymer matter forms a single layer that retains the oil. The sacks will float indefinitely without releasing the oil or allowing it to emulsify, so the oil can remain in place until collection efforts are feasible. The sacks can be burned in situ, or standard fishing boats or specialized collection boats can be used to retrieve the sacks, and the collected material can be burned to capture the energy content of the oil or processed to separate the oil from the polymer. The sacks can be used in conjunction with other, known containment or retrieval equipment, such as booms or skimmers. The system is specifically designed for rapid deployment and efficiency in rough water.
It should be understood that the present invention would in fact enhance the functionality of the above patents by providing a hydraulically actuated and toroidal spacing device for three-dimensional spacing of multiple underwater towed arrays. The towed arrays are further able to be selectively secured to desired locations of the toroidal spacing device and the toroidal spacing device is made to be streamlined for an underwater environment.
Therefore it is an object of this invention to provide a spacing device for easily and automatically separating towed lines in a three-dimensional arrangement.
Another object of this invention is to provide a spacing device hydraulically inflatable for automatically separating towed lines in a three-dimensional arrangement.
Still another object of this invention is to provide a hydraulically inflatable spacing device on which plural towed lines are removably secured.
A still further object of the invention is to provide a hydraulically inflatable toroidal spacing device on which plural towed lines are removably secured.
Yet another object of this invention is to provide a hydraulically inflatable toroidal spacing device on which plural towed lines are removably secured and which is streamlined in an underwater environment.
In accordance with one aspect of this invention, there is provided a hydraulically activated device for spacing plural towed lines in a three-dimensional arrangement that includes a toroidal and inflatable tube member defining an aperture in an opening of the toroid shape. A plurality of connectors each secure a corresponding one of the plural towed lines to the toroidal and inflatable tube member. The toroidal and inflatable tube member is inflated with sea water to a predetermined volumetric configuration suitable to an operating speed range of the towed lines and upon inflation will space the towed lines therearound in a desired pattern. A sheath may also be formed around the toroidal and inflatable tube member, the sheath being formed in cross section as a tear drop or similar streamlined shape.